The invention herein pertains to a system of monitoring pipelines and other fluid pressurized vessels for the probability of leaks. The determination of such probability can be by pressure monitoring of the pipeline, or vessel, -pipeline-, or by monitoring of the velocity of flow therein.
Fluids such as oil, water, and natural gas among others are transported over long distances through varying geographical and weather differing areas. In these days of increased environmental awareness it is important to quickly detect the probability of leak along the pipeline. The monitoring for leakage must take place not only as a precaution against environmental pollution but to prevent uncontrolled hazardous releases.
Since a break or leak in the pipeline gives rise to a pressure drop one can monitor the pipeline from the pressure of the fluid. The prior art therefore has taken the approach to monitor the occurrence of pressure drops. Mention therefore may be made of U.S. Pats. Nos. 2,836,192 and 2,915,042 which reflect mechanical/pneumatic systems designed for this purpose.
Mention may also be mode of patents of Morris T. Covington et al U.S. Pat. Nos. 4,091,658, 4,144,743 and 4,012,944, all of which pertain to electronic leak detection methods. In the Covington et al systems a voltage proportional to flow of the fluid in the pipeline is monitored with a voltage proportional to the flow being differentiated to determine whether any rate of change of pressure exists. Ofttimes such a rate change is indicative of a leak in the pipeline.
One of the major shortcomings of the Covington class of monitoring systems is the fact that such a rate change may not be indicative of a leak in the pipeline. In addition "noise" which is defined as pressure or velocity perturbations arising from causes other than leaks can give rise to false alarms in the monitoring process. Such false alarms cause the persons monitoring the line to spend many hours of lost time in attempts to confirm the reality of alleged breaks in the line.
There is a need for a pipeline monitoring system that does not attempt to monitor actual leaks, but rather the probability of a leak taking place. There is also a need for a pipeline monitoring system that quantifies the data returned to thereby reduce the number of false alarms sounded due to erroneous detection of leaks.
It is an object therefore of this invention to provide a pipeline monitoring system that predicts the probability of a leak in the line by monitoring the pressure.
An important object of this invention is to perform the monitoring task adequately with conventional pipeline instrumentation, e.q. ordinary pressure and flow measuring instruments.
It is another object to provide a system that monitors a pipeline at various locations therealong by a statistical analysis of the probability of a leak.
A further object is to provide a pipeline monitoring system that can quantify the data to thereby reduce the number of false alarms encountered.
A yet further object is to provide a pipeline monitoring system that reduces the rate of false alarm leakage occurrences.
Other objects of the invention will in part be obvious, and will in part appear hereinafter.
The invention accordingly comprises the apparatus possessing the construction, combination of elements and arrangement of parts which are exemplified in the following detailed disclosure, and the scope of which will be recited in the appended claims.